Case Reports A Case of Pneumomediastinum in a Patient With Acute Respiratory Distress Syndrome on Pressure Support Ventilation

During mechanical ventilation for acute respiratory distress syndrome, tidal volume (VT) must be reduced. Once switched to pressure-support ventilation, there is a risk that uncontrolled large VT may be delivered. A 63-year-old man with community-acquired pneumonia required tracheal intubation and mechanical ventilation, with a VT of 6 mL/kg predicted body weight, PEEP of 10 cm H2O, a respiratory rate of 30 breaths/min, and FIO2 of 0.60. Plateau pressure was 22 cm H2O. He improved and received pressure-support. Twelve days later a chest radiograph showed sus-pected air leaks, confirmed via computed tomogram (CT), which showed anterior pneumomedias-tinum. VT received over the previous 3 days had averaged 14 mL/kg predicted body weight. The patient was put back onto volume-controlled mode, and 2 days later there were no air leaks. In pressure-support ventilation, VT must be closely monitored to ensure lung-protective mechanical ventilation. Key words: acute respiratory distress syndrome; ARDS; ventilator-induced lung injury; mechanical ventilation; volutrauma. [Respir Care 2010;55(6):770–773. © 2010 Daedalus Enterprises